Liquid seal vent



Feb. 26, 1935. w, R, MQBLEY I 1,992,875

LIQUID SEAL VENT Filed .Jan. 19, 1931 2 Sheets-Sheet 1 Feb. 2 6, 1935. w MOBLEY 1,992,875

LIQUID SEAL VENT Filed Jan. 19, 1931 2 Sheets-Sheet 2 Patented Feb. 26,1935

UNITED STATES PATENT OFFICE The object of this invention is to prevent the escape of evaporated gases or the like from storage tanks and admit air to permit the contents of the storage tank to be withdrawn.

A further object of this invention is to prevent the escape and ignition of gases from inflammable liquids through the vent pipe.

A still further object of this invention is to act as, a vent and prevent the siphoning of sanitary fixtures.

I accomplish the objects of this invention in the manner described in the accompanying specification and drawings in which:

Fig. l is a side view of the device having a part broken away to show part of the interior.

Fig. 2 is a side view of a modification of the invention.

Similar numerals refer to similar parts throughout the several views in which: 1 is a receptacle containing a liquid 2, which liquid is preferably of such character that it possesses qualities having a minimum of evaporation. A pipe 3 is attached to a storage tank or the like 4 and extends upwards through the liquid 2 to a point above the upper surface of the said liquid as at 5. Immediately above the pipe 3 is located a receptacle 6 through the bottom of which passes a pipe '7 and extends downward through the liquid to near the bottom of the receptacle 1. The liquid 2 does not enter the interior of the pipe 3 but does enter the interior of the pipe "7.

The receptacle 6 is provided with a vent in the form of a goose neck as at 8.

While the receptacle 6 in Fig. 1 is shown substantially the same size as the lower receptacle 1 containing the liquid 2 this chamber may assume proportions as shown at 6 in Fig. 2.

Before describing the invention in operation it is advisable to explain that the loss from evaporation from large storage tanks is tremendous, and further that the gases escapingthrough the customary vent pipes are highly inflammable and constitute a fire hazard. These objectionable features are eliminated by the introduction of this invention which operates as follows:

When a quantity of liquid is drawn from the storage tank 4 the vacuum created in the tank causes air to enter the goose-neck 8 and enter the pipe 7, forcing the liquid contained therein out of the lower end of the pipe into the receptacle 1, after which the air passes through the liquid 2 and above the surface of same and enters the pipe 5 and passes through same into the tank 4.

In the event of a pressure being formed in the tank 4 the gases pass through the pipe 3 into the chamber 1 creating a pressure on the liquid contained therein, causing the said liquid or a portion thereof to be forced through the pipe '7 into the chamber 6.

The quantity of liquid forced from the chamber 1 to the chamber 6 will be governed by the pressure created by expansion of the contents of the tank 4. The hydrostatic head to resist the escape of 'gas will be considerable, namely from the bottom of the pipe 7 to near the top of the chamber 6. 6

When the pressure in the tank 4 has been relieved the liquid 2 will return from the chamber 6 to the chamber 1. In the construction shown in Fig. 2 the pipe 6 takes the place of the chamber 6 of Fig. 1, to receive any liquid which is lifted by gas pressure. By extending the pipe 6 upward the device will be a practical obstacle to the escape of any great amount of gas, by reason of the 'considerable height of the hydrostatic head of the liquid 2. In this construction of Fig. 2 the drawing of petroleum or other liquid from the tank 4 will cause air to pass down the pipe 6 and up through the liquid 2 and down the'pipe 3 into the tank.

While I have described and shown two embodiments of my invention I may, however, employ any modification, providing I do not depart from the true spirit of the invention.

The apparatus will be made of a size and capacity suitable to the strength of the tank and the positive and negative pressures to be encountered.

Having now particularly described and ascertained the nature of my invention and the manner in which I propose to perform same, what I claim as new and desire to secure by United States Letters Patent is:

I claim:

In a fluid seal vent and air supply device for a tank containing vaporable fluid, oil and the like, the combination of lower and upper receptacles, a pipe adapted to be connected with said tank and extending into the lower receptacle and opening into the same above its bottom, a pipe communicating from the upper receptacle and opening into the lower part of the lower receptacle below the upper end of the first pipe, and an air and gas vent for the upper receptacle, the lower receptacle being adapted to contain a suitable trap-fluid of slow vaporization covering the bottom opening of the second pipe and extending up to near the top of the first pipe.

WILLIAM ROBERT MOBLEY. 

